This is javascript toaster library integrated along with Laravel You need to add this file within config/app.php like as

'Toaster' => App\Utils\Toaster::class,

after that you simply can use it within your project using like as

use App\Utils\Toaster;

within file you simply use

Toaster::error("Your failure message.")->error('Another message');

instead of

withFlashDanger / withFlashSuccess

And you need to place following code within your main blade file like as

{!! Toaster::renderToasters() !!}